Ex Vivo Micro-CT in Ophthalmology: Preparation and Contrasting for Non-invasive 3D-Visualisation. / Ex-vivo-Mikro-CT in der Augenheilkunde: Probenbehandlung und -kontrastierung für die 3D-Darstellung.

X-ray-based micro-computed tomography (micro-CT) is a largely non-destructive imaging method for the visualisation and analysis of internal structures in the ex vivo eye and affords high resolution. In contrast to other high-resolution imaging methods, micro-CT enables spatial recording of larger and more complex tissue structures, such as the anterior chamber of the eye. Special contrasting methods help to enhance the absorption properties of soft tissue, that is otherwise only weakly radiopaque. Critical point drying (CPD), as primarily used in scanning electron microscopy, offers an additional tool for improving differential contrast properties in soft tissue. In the visualisation of intraosseous soft tissue, such as the efferent lacrimal ducts, sample treatment by decalcification with ethylenediaminetetraacetic acid and subsequent CPD provides good results for micro-CT. Micro-CT can be used for a wide range of questions in 1. basic research, 2. application-related studies in ophthalmology (e.g. evaluation of the preclinical application of microstents for glaucoma treatment or analysis of the positioning of intraocular lenses) but also 3. as a supplement to ophthalmological histopathology.

[Chromatic Swept-Source Laser Scanning - Concept for a Cell-Resolving Confocal Laser Slit Lamp?] / Chromatic Swept-Source Laser Scanning ­ Konzept für eine zellauflösende konfokale Laserspaltlampe?

BACKGROUND: The in vivo characterisation of corneal epithelial tissue morphology is of considerable importance for diagnosis, disease prognosis, and the development of a treatment strategy for ocular surface diseases. In contrast to many alternative methods, in vivo corneal confocal microscopy (CCM) not only provides a macroscopic description of the corneal tissue but also allows its visualisation with cellular resolution. However, the translation of CCM from research to clinical practice is significantly limited by the complex and still largely manual operation of available CCM systems. In addition, for cross-sectional images, and analogously to conventional slit lamp microscopy, volume data must be acquired in time-consuming depth scans due to the frontal orientation of the image field in CCM, from which depth slices can subsequently be calculated. The pure acquisition time is already in the range of seconds, and additionally, motion artefacts have to be corrected in a sophisticated way. MATERIALS AND METHODS: This paper presents the concept and optics simulation of a new imaging technique based on a swept-source laser in combination with special chromatic optics. Here, the laser periodically changes its wavelength and is focused at different depths due to the wavelength-dependent aberration of the chromatic optics. RESULTS: The optics simulation results promise good optical resolution at a total imaging depth of 145 µm. CONCLUSION: The long-term goal is cell-resolving in vivo corneal confocal microscopy in real time with differently oriented sectioning directions.

[Illustration Techniques in Ophthalmic Textbooks 200 Years Ago - a Platform for the Rostock Glass Eye Collection of Anterior Segment Pathologies from 1860]. / Ophthalmologische Abbildungstechnik vor 200 Jahren ­ der Atlas von Antoine Pierre Demours als Grundlage der Rostocker Kunstaugensammlung.

Very recent research results have demonstrated that the "Rostock Artificial Eye Collection" - assembled 150 years ago with 132 glass modelled exhibits of anterior segment pathologies - is mainly based on the figures of the Atlas of Ophthalmology published by Antoine Pierre Demours in 1818. This article focusses on the analyses of the imaging techniques of this atlas. Present knowledge implies that the author used different colour etching concepts which were partially re-coloured individually. In the opinion of contemporaries, the figures of Demours' atlas represent the climax of scientific imaging techniques. In the academic literature, it is still described as a "recent remarkable masterpiece", even 100 years later.

Therapeutic Strategies in 103 Children with Congenital Microphthalmos. / Therapiestrategien bei 103 Kindern mit kongenitalem Mikrophthalmus.

INTRODUCTION: Congenital microphthalmos can either occur alone (simple microphthalmos) or be associated with other ocular malformations, such as sclerocornea or cataract (complex microphthalmos). As this is a rare condition, there are no uniform recommendations for treatment. MATERIAL AND METHODS: Retrospective case series of 103 patients or a total of 114 eyes with congenital microphthalmos, with reporting of age, sex, visual acuity, pupil reaction, axial length, horizontal width of the palpebral fissure, type of therapy performed and complications. RESULTS: All patients would have been able to be fitted with a prosthesis primarily. The size of the palpebral fissure depended on the underlying findings: "bilateral microphthalmos" < "microphthalmos and healthy fellow eye" < "microphthalmos and fellow anophthalmos". In order to assess visual (residual) function in an infant in the first weeks or months of life, the pupillary response is of the upmost importance in deciding on therapy, especially in unilateral disease, and as assessed with the indirect light response of the healthy eye. In about half of the cases, conservative prosthetic treatment was sufficient. After the successful initial fitting of a prosthesis, the prosthesis was enlarged according to the ocularist's instructions. If the eye length difference was so large that symmetry could not be achieved even with a double-walled prosthesis, volume filling with retrobulbar implanted self-swelling pellet expanders (osmed GmbH, Ilmenau) was offered. In almost one third of the patients, no surgical therapy or prosthetic treatment was performed. The reason for this was usually the presence of minimal visual function of the microphthalmos - ranging from light perception to hand movements. CONCLUSIONS: In the case of visual function of the microphthalmos, surgical measures should not be indicated or only with extreme caution, since the preservation of the existing visual acuity must be regarded as having priority over the cosmetic findings. In cases of asymmetry or underdeveloped palpebral fissure, therapy can be started early in the first year of life without fear of resulting complications.

The Rostock Method for Qualitative and Quantitative Evaluation of Intraocular Lenses. / Die Rostocker Methode zur qualitativen und quantitativen Bewertung von Intraokularlinsen.

BACKGROUND: For quantitative and qualitative evaluation of the imaging properties of IOLs, axial cross-sectional images can be obtained from the 3-dimensional light distribution by means of an optical bench, as is known from light sheet recordings in fluorescein baths. This paper presents a new image-processing algorithm to enhance the quality of generated axial cross-sectional images, and the two methods are then compared. MATERIAL AND METHODS: The 3-dimensional point spread function of a diffractive trifocal IOL (AT LISA tri 839MP, Carl Zeiss Meditec AG, Jena, Germany) was recorded on an optical bench developed in Rostock for different pupil diameters. A specially adapted image processing algorithm was then applied to the measurements, allowing through-focus curves to be generated. In addition, cross-sectional images of the IOLs studied were acquired using the light sheet method in a fluorescein bath. RESULTS: The study clearly shows the superiority of the newly developed method over the light sheet method in terms of image quality. In addition to the individual focal points, fine focal structures as well as halos can be made visible in the cross-sectional images obtained using the new method. In the generated through-focus curves, 3 intensity peaks can be identified, which represent the near, intermediate and far focus of the tested MIOL and cannot be represented by light sheet methods. CONCLUSION: The interaction of the optical bench with the developed image processing algorithm allows a more detailed understanding of the image formation and false light phenomena of IOLs, which was restricted by the technical limitations of the existing light sheet method. In addition, other quantities such as the through-focus curve can be derived quantitatively.

Optical Technologies, Digitally Assisted: Surgical Microscope - quo vadis? / Optische Technologien, digital unterstützt: Operationsmikroskop ­ quo vadis?

Adequate magnification and proper illumination are crucial for success in microsurgical interventions. Thus, surgical microscopes have long been an integral part of modern eye surgery and are at the heart of modern operating theatres. This paper first briefly reviews the history microscopes in ophthalmic surgery - from the initial developments in the mid 19th century to the current state of the art systems with powerful coaxial illumination and fibre-guided xenon or LED light sources. The discussion then turns to current developments, particularly in the area of workflow support and integration of complementary technologies such as intraoperative OCT, "augmented reality", and visual data feeds useful to the surgeon. The last part presents an outlook on future developments, with a particular focus on the digital image chain and intelligent automated assistance.

Treatment Complexity in Primary Open-Angle Glaucoma (POAG): Perspectives on Patient Selection in Micro-Invasive Glaucoma Surgery (MIGS) Using Stents. / Versorgungskomplexität beim primären Offenwinkelglaukom (POWG): Perspektiven zur Patientenauswahl in der mikroinvasiven Glaukomchirurgie (MIGS) mit Stents.

BACKGROUND: Primary open-angle glaucoma (POAG) is still one of the most common causes of impaired vision worldwide, despite the further development of therapy options, and can lead to blindness. Micro-invasive glaucoma surgery (MIGS) using stents aims at reducing intraocular pressure (IOP), as it is the main risk factor. With regard to adherence and adverse drug reactions it also aims at reducing the drug burden on patients. The study investigates under everyday conditions the criteria according to which ophthalmologists in Germany select patients for MIGS using stents. In addition, it will be investigated which patients (could) benefit most from the therapy. MATERIAL AND METHODS: In this qualitative study, 11 narrative interviews were conducted between May 2017 and July 2018 with ophthalmologists working in the hospital or in a private practice. They were interviewed on their experiences in the treatment of POAG with microstents. The interviews were analysed by an interdisciplinary team using the qualitative content analysis. RESULTS: The stages of therapy escalation form the frame of reference for patient selection in MIGS using stents. Only if the IOP cannot be sufficiently reduced by drop therapy or when this causes drug-related side effects that are intolerable for the patients, stents are apparently used as the next higher escalation stage. The intensive post-operative medication and the frequent check-up appointments are perceived as barriers by the interviewees, especially for people with or without disabilities, who are dependent on external help and/or those living in rural areas. The active cooperation of the patients in the demanding aftercare seems to be indispensable for the ophthalmologists. In addition, necessary revisions are sometimes stressful for patients (physical/psychological) and doctors (work organisation/therapy). Against the background of the organisational and economic challenges in the outpatient spectrum of tasks, especially physicians in private practice seem to weigh up carefully for which patients microstent therapy would be reasonable. CONCLUSION: In view of the therapeutic requirements, the current microstent therapy seems to be used in a selected, adherent patient group. Further qualitative and quantitative studies (in other health care regions and structures) are necessary to verify and extend the available results.

Evaluation of Choroidal Melanoma Vascularization by Color Doppler Flow Imaging: An Option for Follow-Up Tumor Control Assessment after CyberKnife®?

Background and Objectives: Thus far, tumor control for choroidal melanoma after teletherapeutic radiation is clinically difficult. In contrast to brachytherapy, the tumor height does not necessarily have to shrink as a result of teletherapy. Therefore, the objective of this study was to evaluate tumor vascularization determined by color Doppler flow imaging (CDFI) as a possible approach for monitoring the therapy response after teletherapy of choroidal melanoma. Materials and Methods: A single-center retrospective pilot study of 24 patients was conducted, all of whom had been diagnosed with choroidal neoplasm, treated and followed up. Besides tumor vascularization, the following parameters were collected: age, gender, tumor entity, location, radiation dose, knowledge of relapse, tumor height, radiation-related complications, occurrence of metastases, visual acuity in logMAR. Results: The level of choroidal melanoma vascularization markedly decreased in all included subjects after treatment with the CyberKnife® technology. Initially, the level of vascularization was 2.1 (SD: 0.76 for n = 10); post-therapeutically, it averaged 0.14 (SD: 0.4). Regarding the tumor apex, CDFI sonography also demonstrated a significant tumor regression (mean value pre-therapeutically: 8.35 mm-SD: 3.92 for n = 10; mean value post-therapeutically: 4.86 mm-SD: 3.21). The level of choroidal melanoma vascularization declined in the patient collective treated with ruthenium-106 brachytherapy. The pre-therapeutic level of vascularization of 2 (SD: 0 for n = 2) decreased significantly to a level of 0 (mean: 0-SD: 0). The tumor height determined by CDFI did not allow any valid statement regarding local tumor control. In contrast to these findings, the patient population of the control group without any radiation therapy did not show any alterations in vascularization. Conclusions: Our data suggest that the determination of the tumor vascularization level using CDFI might be a useful and supplementary course parameter in the follow-up care of choroidal melanoma to monitor the success of treatment. This especially applies to robot-assisted radiotherapy using CyberKnife®. Further studies are necessary to validate the first results of this assessment.

Cataract surgery in Kinshasa-Is there a place for "Monovision"?

OBJECTIVES: Monovision is a method of correcting presbyopia where one eye is focused for far and the other for near vision. It is a simple, cost-effective approach to overcome the loss of accommodation with age and to become spectacles independent. METHODOLOGY: About 50 patients, where bilateral cataract extraction was indicated, were included in this study performed at the St. Joseph's Eye Hospital in Kinshasa (DR Congo). Small incision cataract surgery technique (SICS) was applied with the implantation of 6 mm PMMA lenses in the capsular bag. IOL refractive power choice was made to achieve a post-operative refraction of -0.5 dpt for the eye selected for far vision. The second eye received an implant heading for a post-operative myopia of -1.5 dpt suitable for intermediated and near vision. According to the literature, monovision criteria have been regarded as fulfilled when (a) far vision was 0.5 (logMAR) or better and (b) near vision was P3 (0.40, Decimal 32 cm) or better. Spectacle dependence after bilateral cataract surgery heading for monovision was analysed using a dedicated questionnaire. RESULTS: Out of all 50 patients 22 (44%) fulfilled the above defined criteria of monovision in terms of post-operative refraction and visual acuity. About 19 out of these 22 (86.3%) patients were happy without glasses. Two of them used bifocal spectacles, whereas the remaining patient refused spectacles. About 28 patients did not fulfill monovision criteria. Out of these 28 patients, however, 9 (32.1%) of them are happy without glasses. CONCLUSION: In view of the described local circumstances aiming for monovision after bilateral cataract surgery is a suitable approach to optimise cataract surgical outcomes with no extra costs for surgery but considerable improvement of patient's visual performance in daily life.

Assessment of the Efficacy of Microinvasive Glaucoma Surgery Techniques using an Oculopression Stress Test. / Nicht invasiver Belastungstest zur Funktionsprüfung von mikroinvasiven Glaukomdrainage-Implantaten und Laserchirurgie.

BACKGROUND: Glaucoma is one of the most common causes of blindness worldwide. The only evidence-based treatment to slow down the progression of glaucoma is the reduction of intraocular pressure (IOP) using local medication or through surgery. During the last years, a large number of microinvasive glaucoma surgery techniques (MIGS) has been developed, in order to reduce the IOP in glaucoma patients safely and effectively. Until now, efficacy of MIGS has been assessed mainly according to the postoperative IOP and the number of medications used. Results from long-term studies are rare or not available in the majority of the cases. In order to better evaluate the functionality of MIGS, a new examination method has been developed with the help of a new oculopressor device. In this study the efficacy of different MIGS techniques will be examined using the new oculopressor. MATERIAL/METHODS: At first, glaucoma patients that had previously received a MIGS surgery (iStent inject, XEN Stent, ELT) were examined with the new oculopression test. Their results were compared with those of non-operated patients and healthy individuals. Overall, 38 healthy subjects (group 1), 10 non-operated patients (group 2), 19 patients after iStent inject implantation (group 3), 14 patients after XEN Stent implantation (group 4) and 5 patients after ELT (group 5) were examined. The new examination measures the IOP-reduction that occurs after oculopression and can be seen as an indirect measurement of the outflow facility of the eye. RESULTS: The IOP-reduction after oculopression differed among the study groups. Non-operated patients showed a significantly lower IOP-reduction compared to healthy individuals. Patients after iStent inject and XEN stent implantation showed a larger reduction of IOP after oculopression in relation to non-operated patients and their results approximated those of healthy individuals. These patients needed fewer medications postoperatively in relation to non-operated patients. Patients after ELT showed postoperatively a smaller reduction of IOP after oculopression compared to iStent inject and XEN stent patients. CONCLUSION: MIGS can increase the outflow facility of the eye in patients with glaucoma. Though ELT had the lowest impact on the aqueous outflow among the studied procedures in this study. The new test can help in the evaluation of current and further development of new MIGS in the future.